Mucosal candidiasis unresponsive to oral azole antifungal medication is a common occurrence in patients with advanced HIV infection; also, some patients are unable to take oral medications because of discomfort due to candidiasis. The purpose of this study is to compare the efficacy, safety, and tolerability of a new intravenous antifungal medication, MK-0991, with amphotericin B (which is currently the primary therapy for resistant candidiasis), in patients requiring intravenous therapy for mucosal candidiasis.